Not Applicable
This invention has been created without the sponsorship or funding of any federally sponsored research or development program.
The present invention is directed generally to an improved heating system for a building. The invention is directed more specifically to a heating system which recovers or recuperates heat of combustion from the exhaust gases from a conventional boiler or furnace that would normally be lost to the environment.
A typical furnace is usually constructed of cast iron or steel containing an interior space. A burner unit projects a flame into this space, thereby, producing both radiant and convective heat energy. This space is surrounded on five sides by a hollow jacket of either cast iron or steel. The fluid, typically water, that resides within this jacket absorbs both the radiant heat and convective heat through conduction across the jacket wall. To enhance heat transfer, some jacket walls possess fins protruding in the combustion gas flow stream. These fins may also protrude into the fluid as well. The additional face area provided by these fins increases the quantity of heat that can be absorbed. The water in the water jacket is heated to a predetermined temperature and then pumped or otherwise circulated through a heat exchanger system within the building for space or process heating. The cooled water returns, by pumping or gravity, to the water jacket to be reheated and the cycle is repeated. Furnace heating can occur with a plurality of fuels such as wood, fuel, oil, or gas. Most of this combustion energy is imparted to the water within the jacket. Nevertheless, the combustion gas leaving the boiler possesses recoverable energy which is, otherwise, lost to the environment.
It is, therefore, a principal object of the invention to provide a heating system for a building which also recovers heat from the exhaust gases from a furnace.
A further object of the invention is the provision of auxiliary heat recovery system for a conventional heating system for recovering heat from the exhaust gases from a furnace.
Another object of the invention is the provision of a supplemental fluid circulation system for a heating system for recovering heat from furnace exhaust gases and for transferring the recovered heat to the main fluid circulation system of the heating system.
A still further object of the invention is to provide supplemental fluid circulation system for a heating system which draws relatively cool fluid from the main fluid circulation system, transfers heat from the furnace exhaust gases to the relatively cool fluid and returns the heated fluid to a portion of the main fluid circulation system which contains relatively warm fluid.
Still another object of the invention is the provision of an improved gas-to-water heat exchange apparatus for recovering heat of exhaust gases at the flue of a heating system.
In general, the invention consists of a heating system for a building that includes a furnace having a water jacket surrounding a burner unit. Heated water is circulated from the water jacket to a heat exchange system in the building such as radiators and the water is returned to the water jacket through a return conduit to be reheated. Water from the jackets is also circulated through a supplemental conduit through a gas tube water heat exchange apparatus located at the exhaust flue from the furnace for recovering heat from the exhaust gases. Water which is heated by the exhaust gases returns to the primary circulation system. More specifically, water flows from the cooler portions of the water jacket and/or the return conduit portion of the main circulation system to the gas-to-water heat exchange unit. The water then flows from the gas-to-water heat exchange unit to the relatively warmer portions of the jacket and/or to the primary conduit that delivers water from the jacket to the heat exchange system of the building.